11:37am

13.7: Cosmos And Culture

A Human-Driven Mass Extinction: Good Or Bad?

Will the distant future give rise to exhibits of a human past long gone, much as we gawk today at representations of a dinosaur age we can only imagine?

Aamir QureshiAFP/Getty Images

Odds are good that there's a mass extinction going on right now. It will be only one of six in the entire history of the planet. In the past these great die-offs have been caused by asteroid impacts and rapid, devastating climate change driven by volcanism.

This time it's driven by you and me.

How does that make you feel? How should that make you feel? The answer to this question depends mightily on what you think of as nature and where you think we fit into it.

Chris Thomas is one of the ecologists who first recognized the ongoing anthropogenic mass extinction. In 2004 he forecast that a rise of 2 degrees in global temperature would commit millions of species to extinction. But in a recent interview with New Scientist, he discussed the other side of mass extinctions — the rise of new species:

We worry about extinctions in the era of humans. But at the same time we are seeing an evolutionary surge. The seeds of recovery are already visible. New species are beginning to emerge. Of course many will fail, but others will become the lineages of the future.

This may seem like crazy talk, especially from a scientist who has done so much to publicize our negative effect on existing bio-diversity. But a deeper read of Thomas' perspective highlights the quandary we humans face. All previous mass extinctions were followed by an explosion of evolutionary creativity. What is remarkable, in Thomas' view, is that scientists are already seeing the first hints of this new species:

"Genes are jumping around. Molecular genetics is finding that hybridization between species is more common than previously suspected."

From newly hybridized fruit flies adapting to colonize an invasive species of honeysuckles in the United States to new wild populations of rhododendrons emerging from mixes of European and North American species, Thomas sees movement and change in nature as it responds to global warming and other human effects.

So this is a good thing, right? Is it finally time to rejoice in climate change? Well, it all depends on whom you ask.

Sixty-five million years ago, our tiny mammalian ancestors were overjoyed when an asteroid wiped out the dinosaurs. The evolutionary bounce-back from mass extinction means that life on Earth will do just fine, thank you very much. But that recognition forces us to see the real challenge of climate change.

The danger is not to the planet but to our civilization on the planet.

This uber-technological civilization we have constructed so quickly is a network of networks (energy, transportation, economic, information and social networks). We all rely on those networks to keep food appearing in grocery stores and electricity flowing into the plugs in walls. To scientists studying the overlapping webs that define civilization, it has become clear how vulnerable these systems are to not just risk but hyperrisk — the cascade of failures that can be triggered by even small disruptions. Thus, the real dilemma we face is keeping this machine we call civilization working in a rapidly changing natural world.

The emphasis on reducing climate change is a question of sustainability. What we often miss is that what we're trying to sustain is us. The rest of the planet will just go along on its merry way. In that sense, the very meaning of "nature" will likely change.

Thomas argues that not every change we see happening in nature can, or should be, resisted. A "narrow preservationist agenda," he argues, can reduce the capacity of nature to respond to the environmental changes that we are foisting on the world. For example, Thomas wants to see migration corridors opened up through human-dominated areas for species whose habitat is moving as the climate changes.

In the end, our ability to recognize, explicitly and exactly, what's at stake will determine our ability to respond effectively to the climate change we are creating. We will have to understand our place in nature with far more acuity than the fist-and-hammer approach we've used for the past few hundred years.

The danger in failing to do so is that nature will just pass us by. As Thomas says:

"If nature can bounce back from an asteroid hit, it can probably bounce back from us."

You can keep up with more of what Adam Frank is thinking on Facebook and on Twitter: @AdamFrank4